AKT · Acute care/Cardiac & respiratory

Tension pneumothorax

One-way air leak → progressive intrapleural pressure

Overview

Air trapped under increasing pressure in the pleural space shifts the mediastinum and obstructs venous return — obstructive shock. A clinical diagnosis and an immediate-decompression emergency: do NOT wait for a chest X-ray.

Recognise

Severe respiratory distress, hypoxia, tachycardia, hypotension
Absent breath sounds + hyper-resonance on the affected side; tracheal deviation AWAY; distended neck veins
Often after trauma, ventilation, or in known lung disease

Red flags

Haemodynamic collapse — this is a clinical diagnosis; decompress immediately without imaging

Differentials & how to tell them apart

Massive haemothoraxabsent breath sounds but DULL percussion + shock — also needs drainage

Cardiac tamponademuffled heart sounds, raised JVP, pulsus paradoxus — but breath sounds normal

Simple pneumothoraxno haemodynamic compromise / mediastinal shift

Investigations

CLINICAL diagnosis — treat before imaging. After decompression, CXR confirms and guides the chest drain.

Management

Immediate decompression (large-bore cannula 2nd ICS MCL or finger thoracostomy) → chest drain

1Immediate needle decompression (large-bore cannula, 2nd intercostal space mid-clavicular line, or 4th/5th ICS anterior axillary per updated guidance) — then a definitive chest drain.Gate: Do NOT wait for a chest X-ray if there is haemodynamic compromise — decompress on clinical grounds
2Insert an intercostal chest drain; treat the underlying cause; CXR to confirm.

High-flow oxygen — adjunct

No drug — needle/finger decompression then chest drain — mechanical relief is the treatment

Key points

Tracheal deviation is a late sign. Treat clinically — imaging delay can be fatal. Dull percussion points to haemothorax instead.

Monitor & prognosis

Re-expansion on CXR, drain function/swing, ongoing air leak.

Rapidly fatal if untreated; excellent after timely decompression.

Source: ATLS; NICE NG39 (major trauma)